Effects of epigallocatechin-3-gallate on 1-methyl-4-phenylpyridinium ion-induced apoptosis in rat PC12 cells

AIM: To investigate the effects of epigallocatechin-3-gallate (EGCG) on 1-methyl-4-phenylpyridinium ion (MPP+)-induced apoptosis in rat pheochromocytoma (PC12) cells and to explore the relationships between its roles of anti-oxidation, intracellular calcium homeostasis and anti-apoptosis. METHODS: Rat PC12 cells were pretreated with vehicle control or EGCG (10, 50, and 100 μmol/L) for 30 min, then cultured with MPP+ (900 μmol/L) for 24 h. The cell viability and apoptosis were monitored by MTT assay and flow cytometry using Annexin V and PI. The activity of intracellular reactive oxygen species (ROS), contents of superoxide dismutase (SOD) and malondialdehyde (MDA), cytoplasmic Ca2+ density and apoptotic morphology of mitochondria were examined by fluorescent plate-based assays, confocal microscope, and transmission electron microscope, respectively. RESULTS: MPP+ impaired the PC12 cells in a concentration-dependent pattern and induced apoptosis of the cells (31% versus control). Compared with the control, the cells pretreated with EGCG showed markedly higher rate of viability and lower apoptosis. Meanwhile, EGCG pretreatment significantly increased the SOD activity and decreased the levels of MDA and ROS. Interestingly, EGCG also decreased the concentration of cytoplasmic Ca2+ and improved the morphology of mitochondria. CONCLUSION: EGCG exhibits inhibitory effects on MPP+-induced apoptosis in rat PC12 cells, which is possibly associated with increasing the cell ability of anti-oxidation and decreasing the concentration of cytoplasmic Ca2+.